Abstract

A polarization-encoded optical shadow-casting (POSC) system¹ processes 2-D coded input in parallel. Light emitting diodes (LEDs) shift and overlap the shadow of the overlapped input pattern from which a decoding mask spatially filters and detects the output. Our current work involves designing an arithmetic logic unit (ALU) which is the heart of general purpose computing. For an ALU, sixteen logical operations of two variables and addition/subtraction result of three binary variables need to be generated. To simplify the design process, the result of three binary variables need to be generated. To simplify the design process, the resulting ALU truth table with twenty-four entries, is partitioned² into smaller sections, so that each section can be realized with smaller pixel inputs. In the sectional arrangement, inputs A and B are controlled by the third input pixel C to generate both arithmetic and logical output, separately, similar to a single instruction multiple data flow machine. The application of truth table partitioning results in a smaller pixel size, only two pixel subcells for each input. The input coding and source LED pattern are also provided.

© 1991 Optical Society of America